vco

Contains settings that control the Main PLL VCO. The VCO output frequency is the input frequency multiplied by the numerator (M+1) and divided by the denominator (N+1). The VCO input clock source is always eosc1_clk. Fields are only reset by a cold reset.
Module Instance Base Address Register Address
clkmgr 0xFFD04000 0xFFD04040

Offset: 0x40

Access: RW

Important: To prevent indeterminate system behavior, reserved areas of memory must not be accessed by software or hardware. Any area of the memory map that is not explicitly defined as a register space or accessible memory is considered reserved.
Bit Fields
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16

regextsel

RW 0x1

outreset

RW 0x0

outresetall

RW 0x0

Reserved

denom

RW 0x1

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

numer

RW 0x1

pwrdn

RW 0x1

en

RW 0x0

bgpwrdn

RW 0x1

vco Fields

Bit Name Description Access Reset
31 regextsel

If set to '1', the external regulator is selected for the PLL. If set to '0', the internal regulator is slected. It is strongly recommended to select the external regulator while the PLL is not enabled (in reset), and then disable the external regulater once the PLL becomes enabled. Software should simulateously update the 'Enable' bit and the 'External Regulator Input Select' in the same write access to the VCO register. When the 'Enable' bit is clear, the 'External Regulator Input Select' should be set, and vice versa. The reset value of this bit is applied on a cold reset; warm reset has no effect on this bit.

RW 0x1
30:25 outreset

Resets the individual PLL output counter. For software to change the PLL output counter without producing glitches on the respective clock, SW must set the VCO register respective Output Counter Reset bit. Software then polls the respective Output Counter Reset Acknowledge bit in the Output Counter Reset Ack Status Register. Software then writes the appropriate counter register, and then clears the respective VCO register Output Counter Reset bit. LSB 'outreset[0]' corresponds to PLL output clock C0, etc. If set to '1', reset output divider, no clock output from counter. If set to '0', counter is not reset. The reset value of this bit is applied on a cold reset; warm reset has no effect on this bit.

RW 0x0
24 outresetall

Before releasing Bypass, All Output Counter Reset must be set and cleared by software for correct clock operation. If '1', Reset phase multiplexer and all output counter state. So that after the assertion all the clocks output are start from rising edge align. If '0', phase multiplexer and output counter state not reset and no change to the phase of the clock outputs.

RW 0x0
21:16 denom

Denominator in VCO output frequency equation. For incremental frequency change, if the new value lead to less than 20% of the frequency change, this value can be changed without resetting the PLL. The Numerator and Denominator can not be changed at the same time for incremental frequency changed.

RW 0x1
15:3 numer

Numerator in VCO output frequency equation. Note that the valid range for this field is 0x000 to 0xFFF (0 to 4095). The most significant bit of this field is reserved and should not be used. For incremental frequency change, if the new value lead to less than 20% of the frequency change, this value can be changed without resetting the PLL. The Numerator and Denominator can not be changed at the same time for incremental frequency changed.

RW 0x1
2 pwrdn

If '1', power down analog circuitry. If '0', analog circuitry not powered down.

RW 0x1
1 en

If '1', VCO is enabled. If '0', VCO is in reset.

RW 0x0
0 bgpwrdn

If '1', powers down bandgap. If '0', bandgap is not power down.

RW 0x1